members vs volunteers

I am reading the report of the Commission on the Future of Volunteering and I starting thinking about the similarities between members and volunteers, and got myself into a bit of a muddle - where does one end and the other begin? Is an active member actually a volunteer? Or does the title of membership denote a more committed position? Or perhaps just the addition of a financial committment in the form of subscription?

Now that we are asking Fellows to be more involved; to give time, ideas and support to the Networks platform and each other, it occured to me that this is more akin to volunteering than ever before, and the report might therefore have some interesting advice as to how we attract people to join the RSA and get them involved.

I am only halfway through right now, but I'll make a note of anything that catches my eye and post it later.